1. Field
Embodiments relate to light emitting modules.
2. Background
Light emitting devices, such as Light Emitting Diodes (LEDs) or Laser Diodes (LDs), which use group III-V or group II-VI compound semiconductors, are capable of emitting light of various colors, such as red, green, blue, and ultraviolet light, and the like, owing to developments of device materials and thin film growth technologies. Moreover, these light emitting devices are capable of emitting white light with high efficiency through use of a fluorescent substance or color combination, and have advantages of low power consumption, semi-permanent lifespan, fast response time, safety, and environmental friendliness as compared to conventional light sources, such as fluorescent lamps, incandescent lamps, and the like.
Accordingly, application sectors of light emitting devices are expanded up to transmitting modules of optical communication means, LED backlights to replace Cold Cathode Fluorescence Lamps (CCFLs) which serve as backlights of Liquid Crystal Display (LCD) apparatuses, white LED lighting apparatuses to replace fluorescent lamps or incandescent lamps, head lights of vehicles, and traffic lights.
FIG. 1 is a plan view schematically showing a general light emitting module.
The light emitting module of FIG. 1 includes a plurality of light emitting devices D11 to D14 and D21 to D24 disposed on a body 10. The plurality of light emitting devices D11 to D14 and D21 to D24 are disposed on the body 10 and are spaced apart from one another by a constant distance.
In this case, the number of the light emitting devices D11 to D14 and D21 to D24 to be turned on is gradually increased according to the level of power applied from an external source. For instance, the light emitting devices D11 and D21 may be turned on when a drive voltage having a first level is applied, the light emitting devices D11, D12, D21, and D22 may be turned on when a drive voltage having a second level greater than the first level is applied, the light emitting devices D11 to D13 and D21 to D23 may be turned on when a drive voltage having a third level greater than the second level is applied, and the light emitting devices D11 to D14 and D21 to D24 may be turned on when a drive voltage having a fourth level greater than the third level is applied. In this case, light may be one-sidedly emitted from the top of the light emitting module due to different power consumption or different illuminances of the light emitting devices D11 to D14 and D21 to D24, which may cause uneven light emission.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.